Networks & The Internet

Networks

-Reduce hardware and software costs
-Provide access to a wide range of services and specialized peripheral devices
-enable people to work together, regardless of time and place.

OSI (Open Systems Interconnection) Model

Sender:

• application
• presentation
• session
• transport
• network
• data link
• physical

(Travels through the internet)

Receiver:

• Application
• Presentation
• Session
• Transport
• Network
• Data Link
• Physical

Data transmitted in packets

3 main components of computer & information security:

1. Confidentiality - prevention of unauthorized disclosure
2. Integrity - prevent unauthorized modification
3. Availability - prevent unauthorized withholding

• Hardware more visible to criminals. Easy to add, remove, and change

Basics in protecting security

• passwords
• firewall
• anti-virus/anti-spyware software
• patches
• backups

inception/theft - unauthorized copying

LAN: Local Area Network

• extended across a limited geographic area

WAN: Wide Area Network

• extends across a larger geographic area

The internet:

• interconnected networks
• the worlds biggest WAN

Network Typology

• Client - Server
  • Client: Local Server
  • Server: Remote system that receives and handle requests from many clients concurrently
• Peer to Peer (P2P)
  • each entity can act as a client or a server
    • no central control
  • Used For:
    • File exchanges
    • workgroups
• Bus or Tree
  • features a "backbone" connection
    • connects all computers
  • Smaller client-servers or P2P style networks branch off

Network Cables
Most wired networks use twisted pair cables

• UTP: unshielded twisted pair
• STP: shielded twisted pair
• Connector: RJ-45

Some networks use:

• Coaxial cable
• Fiber optic cable